| 摘要 |
PURPOSE:To remove a shrinkage cavity in the inner surface of a cast steel tube by remelting the inner surface of the steel pipe with high energy heat source. CONSTITUTION:A centrifugal cast steel tube 1 is horizontally supported to a rotary receiving tables 5 and connected to a rotary driving device and rotated at low speed. A torch 2 for welding with plasma power is connected to a longitudinal feeding device 3 and provided in the tube so as to make a nozzle hole face downward, and is movable by the setting distance in the axial direction of the tube. The torch 2 is connected to a weaving device separately to the longitudinal feeding device 3, and the weaving is executed in the tube axial direction of the tube in a prescribed weaving width. And the torch 2 is moved to the axial direction by the longitudinal feeding device 3 corresponding to the weaving width at each one turning of the tube 1, thereby the weaving is again started from the moved position. By remelting the inner surface of the tube at high temp. of the plasma jet, the shrinkage cavity is eliminated. |
